Developer for facsimile printing machine



Jan. 26, 1965 w. J. LABEN ETAL DEVELOPER FOR FACSIMILE PRINTING MACHINE '7 Sheets-Sheet 1 Filed Jan. 31, 1963 INVENTORS WALLACE J. LABEN CARL G. Roam/vs BY JOHN C. SCHMIDT amfifia [OW-F WM ATTYs.

Jan. 26, 1965 w. J. LABEN ETAL 3,167,455

DEVELOPER FOR FACSIMILE PRINTING MACHINE Filed Jan. 31, 1963 7 Sheets-Sheet 2 FIG. 2

Jan. 26, 1965 w. J. LABEN ETAL 3,167,455

DEVELOPER FOR FACSIMILE PRINTING MACHINE 7 Sheets-Sheet 5 Filed Jan. 31, 1965 INVENTORS WALLACE J. (.Aat-IN CARL G. ROBBINS yJo/m c. SCHMIDT Jan. 26, 1965 w. .1. LABEN ETAL DEVELOPER FOR FACSIMILE PRINTING MACHINE '7 Sheets-Sheet 4 Filed Jan. 31, 1963 5 a w 0 s T T- 2 T w d A m JR, an A mm wch Jan. 26, 1965 w. J. LABEN ETAL 3,167,455

DEVELOPER FOR FACSIMILE PRINTING MACHINE Filed Jan. 31, 1963 7 h t t 5 INVENTORS WALLACE J. LABEH CARL Robb/NS BY JOHN C. Scum/o1- Jan. 26, 1965 w. J. LABEN ETAL DEVELOPER FOR FACSIMILE PRINTING MACHINE 7 Sheets-Sheet 6 Filed Jan. 31, 1965 QON mi T mr maamwn V 5 M v N o J R 5.5 LLN 3 WCJ m Y M Jan. 26, 1965 w. J. LABEN ETAL DEVELOPER FOR FACSIMILE PRINTING MACHINE 7 Sheets-Sheet '7 Filed Jan. 31, 1963 5 R N r m m z T. QIW A W MMW mi? 9.52% as A A8 nLN i m W617 Y I H 2 w @W United States Patent Ofilice 3,l6?,455 Patented Jan. 26, 1965 3,167,455 DEVELUTPER FOR FAcsrMrLE PRENTENG MACHINE Wallace l. Laban, (Ihicago, Carl G. Robbins, Des Elaines, and John C. Schmidt, Elrnwood Park, Ill., assigmors to A. B. Biol; Company, Chicago, Ill, a corporation of Illinois Filed l en. 31, 1963, Ser. No. 255,381 7 Claims. (Cl. 11863=7) This invention relates to a new and improved developer mechanism for facsimile printing machines or other similar machines in which it is desired to develop a latent electrostatic image on a web or sheet of paper or other similar material.

One object of the present invention is to provide a new and improved developer mechanism which is adapted to apply a powdered or finely divided developer composition to a sheet or web of paper or the like, so as to develop a latent electrostatic image which may have been formed on the paper or other copy sheet.

A further object is to provide a new and improved developer adapted to apply a finely divided developer composition comprising a toner powder adapted to adhere to the electrostatic image, the toner powder eing applied with the aid of a carrier powder, such as powdered iron or other magnetic material, for example.

It is another object of the present invention to provide a new and improved developer mechanism having means for constantly agitating and circulating the powdered developer composition, so that the toner powder will be mixed thoroughly with the carrier powder.

A further object is to provide a new and improved developer mechanism having one or more magnetic applicator rollers for carrying the powdered developer composition, together with means for continuously removing the old supply of developer composition from the rollers, while applying a new supply of the developer composition thereto.

It is a further object to provide a new and improved developer mechanism having effective and convenient means for selectively activating and deactivating the developer mechanism.

Another object is to provide a new and improved developer mechanism having means for selectivity introducing additional toner powder into the developer composition.

A further object is to provide a new and improved developer mechanism of the foregoing character in which the toner powder is introduced under precise control, and in such a manner as to avoid spillage andwastage of the toner powder.

Further objects and advantages of the present invention will appear from the following description, taken the accompanying drawings, in which:

FIG. 1 is a general diagrammatic elevational view showing the over-all layout of a facsimile printing machine having a developer mechanism to be described as an illustrative embodiment of the present invention.

FlG. 2 is a diagrammatic side elevational View showing the developer mechanism.

FIG. 3 is a diagrammatic elcvational section of the developer, showing the mechanism for stopping and starting the action of the developer.

FIG. 4 is a diagrammatic developed horizontal section taken through the developer.

FIG. 5 is a fragmentary elevational view showing a portion of a latching arrangement employed on the developer mechanism.

FIG. 6 is a diagrammatic plan view of the developer.

FIG. 7 is a diagrammatic developed elevational section through the developer mechanism.

FIG. 8 is a diagrammatic elevation showing the gear train for the developer.

FIG. 9 is a diagrammatic plan view showing one end portion of the developer mechanism.

FIG. 10 is an elevational section showing the device for feeding the toner powder into the developer mechanism.

FIG. 11 is a fragmentary view corresponding generally to the lower portion of FIG. 10 but showing the agitator for the toner in a changed position.

FIG. 12 is an clevational view showing the selectively operable drive for the device which feeds the toner to the developer.

FIG. 13 is a fragmentary sectional view, taken generally along a line l313 in FIG. 12.

PEG. 14 is a fragmentary sectional view taken generally along the line 14 in MG. 10.

FIG. 15 is a fragmentary sectional view, taken generally along the line 15-15 in FIG. 10.

PEG. 16 is a fragmentary sectional view, taken generally along the line l6l6 in FIG. 12.

The present invention is applicable to developer mechanisms for any type of machine in which it is desired to develop a latent electrostatic image by applying a toner powder to the copy sheet on which the electrostatic image has been formed. As an example of such a machine, FIG. 1 illustrates the general layout of a facsimile printing machine 5t which employs an electronic printing tube 5.2 which is adapted to receive the electrical facsimile signals and to produce electrostatic images corresponding to the documents being transmitted. The electrostatic images are produced on a web 54 made of paper or other suitable material. Tue latent electrostatic images are then rendered visible by means of a developer mechanism A fmer or fuser device 58 may be employed so that the developed images will be rendered permanent.

The illustrated developer comprises a trough or other receptacle 6% adapted to hold a supply of finely divided or powdered developer composition 62 which is applied to the surface of the web 54, after the latent electrostatic image has been produced on the web by the electronic printing tube 52. The powdered material 62 may comprise a mixture of a finely divided carrier, such as powdered iron or other magnetic material, and a finely powdered toner material adapted to adhere to the latent electrostatic image. The toner powder may comprise various suitable plastics capable of being fused to the surface of the paper web. The toner material is normally black or some other dark color. Of course, the toner powder adheres to the latent image due to electrostatic attraction. In this way, the latent image is rendered visible by the toner. The iron powder or carrier is retained in the developer 56.

The fixer or fuser 58 is adapted to develop sutlicient heat to fuse the toner particles so that the toner will adhere permanently to the web 54. In this case, the fuser 58 comprises a plurality of tubular heat lamps 64 mounted in a trough-shaped reflector 66 and directed upon the web 54 after it has left the developer 5%.

in the illustrated machine, the web 54 is unrolled from a supply roll 68. After passing over a guide roller 70, the Web 54 passes around a pair of S-lock feed rollers 72 and 74, and then over the main drive roller 76. In this case, the rollers 72, 74 and '76 may be continuously driven. However, the web 54 is not advanced unless it is pressed against the main drive roller 76 by a nip roller 78 which is movable into and out of engagement with the web. The nip roller 78 may be frictionally rotated by the web 54. A one-way roller Si) engages the web above the roller 76 to prevent the web from backing up when the nip roller 78 is out of engagement with the web.

From the rollers 76 and 78, the web 54 passes to a severing device 82, which may comprise a movable knife 84 acting in cooperation with a stationary bed knife 86. The severing device is adapted to cut off sheets from the leading end of the web so that the reproduced documents will be severed from the web as separate sheets. The reproduced document may be of any desired length.

At the beginning of each cycle of the machine, the nip roller 78 is moved toward the main drive roller 76 so as to press the Web 54 against the roller 76.- The rollers 72, 74 and 76 then advance the leading end of the web past the severing device 82 to a main cylinder or drum 88. Means may be provided on the cylinder 88 to take the leading end of the web and to carry the web around the cylinder and past the electronic printing tube 52 and the developer 56. For example, such means may take the form of vacuum porting in the cylinder 88, whereby the web is sucked against the surface of the cylinder.

From the main cylinder 88, the leading end of the web passes to a fuser cylinder 90 which also has means for taking and carrying the web. The cylinder 90 carries the web past the heat lamp 64 of the fuser 58.

After passing around the fuser cylinder 90, the leading end of the web is fed between two sets of nip rollers 92 and 94, and then between two more sets of nip rollers 96 and 98. The rollers 92, 94, 96 and 98 may be driven so as to rotate continuously. Thus, these rollers propel the web after it leaves the fuser cylinder 90.

From the nip rollers 96 and 98, the web is directed to a delivery conveyor 100, which carries the facsimile copy to the front end of the machine and deposits the copy in a receiving tray 102. The copy is severed from the web 54- by the cutting knife 84, which may be actuated upon receipt of a cutoff signal from the transmitting station. Simultaneously with the action of the knife 84, the nip roller 78 may be disengaged from the web, whereupon the web stops its forward movement. However, the severed sheet is propelled by the cylinders 88 and 90 and the rollers 9296 to the delivery conveyor 100.

In this case, the delivery conveyor 100 comprises a plurality of laterally spaced endless belts or tapes 104 which are strong around end rollers 106 and 108 and intermediate rollers 110 and 112. Nip rollers 114 engage the roller 108 so as to propel the facsimile copy into the receiving tray 102. The facsimile copy is held against the tapes 104 between the rollers 106 and 110 by a series of rollers 116 which may take the form of balls rotatably mounted on guide bars or members 118 disposed over the tapes. The delivery conveyor 100 may be continuously driven so that the tapes 104 are continuously in motion.

For further details of the facsimile printing machine, reference may be had to the copending application of Wallace R. Fowlie and Wallace J. Laben, Serial No. 206,503, filed June 29, 1962. i As shown to advantage in FIG. 3, the illustrated developer 56 comprises two applicator rollers 13 0 and 132 which are rotatably mounted in the trough or receptacle 60 and are adapted to apply the powdered developer composition to the paper as it travels around the main cylinder 88. In this case, one end of the trough 60 is supported by a pair of latches or hooks 134 (FIG. 2) which are swingable about pivots 136 and are adapted to be received under'bearings 138 on the shaft 140 for the roller 132. Spring-type locking plungers 142 are employed to retain the hooks 134 in their locked positions. The plungers 142 may be pulled out so that the hooks 134 may be swung away from the bearings 138 to provide for easy removal of the developer mechanism from the machine.

The other end of the developer receptacle 60 is supported by a hook or latch 144 which is swingable under a cross rod 146 on the receptacle 60. The latch 144 is secured to a shaft 148. Levers 150 (FIG. 5) are mounted on the shaft 148 for releasing and engaging the hook or latch 144. Each lever 150 is movable between stop pins 152 and 154. The cross rod 146 is eccentrically mounted on rotatable hubs 156. By turning the hubs 156, the exact elevation of the developer 56 may be adjusted. When the hook 144 is swung away from the rod 146, the developer receptacle 60 may be swung down to afford easy access to the top of the receptacle, for cleaning or other servicing.

As shown to advantage in FIG. 4, each of the illustrated applicator rollers and 132 comprises a plurality of permanent magnets mounted within a nonmagnetic, substantially cylindrical shell 162 which may be made of brass or other suitable material. In this case, each of the permanent magnets 160 is in the form of a circular disk or ring. The magnets 160 are arranged in groups of two or three with nonmagnetic spacers 164, made of fiber or other suitable material, disposed between groups. Within each group, the poles of the magnets are given the same orientation. However, the poles of adjacent groups are oppositely or differently oriented.

The magnets 160 attract the powdered iron which is employed as a carrier in the finely divided developer composition. Thus, the developer composition adheres to the outside of each of the rollers 130 and 132 in a fairly thick layer. The powdered iron or other magnetic material carries the toner powder With'it so that the toner powder may be applied to the paper web 54 as it passes around the cylinder 88. As shown to advantage in FIG. 3, there is a definite spacing between the main cylinder 88 and each of the rollers 130 and 132. Thus, the rollers 130 and 132 do not actually come into engagement with the paper web passing around the main cylinder 88. However, when the .developer is in operation, the layer of powdered material adhering to each of the rollers 130 and 132 comes into engagement with paper web so as to develop the latent electrostatic image on the web.

The rollers 130 and 132 might be driven intermittently to stop and start the operation of the developer. However, in this instance, the rollers are driven continuously by a gear train which is shown to advantage in FIG. 8. Thus, a gear is connected to the roller 132 and is adapted to mesh with a smaller gear 172 which in turn meshes with a gear 174 secured to the main cylinder 88. Another gear 176 is also secured to the roller 132 and is adapted to mesh with a gear 178 meshing in turn with a gear 180, which is connected to the roller 130.

To circulate the powdered developer composition, the developer is provided with an inclined double-edged scraper 184 (FIG. 3) which is positioned between the rollers 130 and 132. During the normal operation of the developer, the scraper 184 scrapes the developer composition 01f the roller 130 after the roller 130 has passed the main cylinder 88. The scraped material flows down the scraper and is taken up by the other roller 132 so that the material is again carried past the main cylinder 88. The scraper 184 removes much of the material from the lower portion of the roller 132, whereupon the material falls into the lower portion of the developer receptacle 60. Thus, the scraper 184 has two scraping edges: an upper scraping edge 186, which is adapted to remove the developer composition from the upper portion of the first applicator roller 130; and alower scraping edge 188, adapted to remove material from the lower portion of the other applicator roller 132. V

The developer receptacle 60 is preferably formed with a well 190, within which the developer composition may be circulated and agitated by two augers 192 and 194 which are driven continuously, preferably in opposite directions. Thus, one of the angers carries the powdered material longitudinally in one direction, while the other auger carries the material in the opposite direction. In this case, the augers 192 and 194 are fitted with drive gears 196 and 198 which mesh with each other. The gear 196 meshes with the continuously driven gear 178.

In the illustrated construction, the operation of the developer 56 is adapted to be started and stopped by two movable scrapers 200 and 202 which are adapted to scrape the powdered developer composition off the rollers 130 and 132. When the developer 56 is in normal operation, the scrapers 2% and 262 are retracted away from the rollers 13-9 and 132 so that the rollers are able to carry the powdered develo, lug material upwardly against the paper web on the main cylinder 88. The scrapers 290 and 202 are mounted on levers 2M and 2% for movement toward and away from the roller 13% and 132. Springs 208 and 21b bias the levers 2G and 266 in such a direction as to move the scrapers 296 and 292 toward the rollers 130 and 132. The scrapers 298 and 2592 are adapted to be moved away from the rollers 13% and 132 by solenoids 212 and 214. Thus, a link 216 is connected between the solenoid 212 and a lever 213 having an arm 22%) which is engageable with a stop pin 222 on the lever 224. A return spring 22 3 biases the lever 21% away from the pin 222.

Similarly, a link 226 is connected between the solenoid 214 and a lever 22% having an arm 23% which is engageable with a pin 232 on the lever 2%. The solenoid 214 acts against a return spring 234.

When the developer is operating, both of the solenoids 212 and 214- are energized so as to hold the scra; ers 239 and 202 away from the rollers 130 and 132. When the developer is shut down, the solenoids 212 and 214 are deenergized, preferably in sequence, so as to permit the scrapers 200 and 292 to move toward the rollers 139 and 132. In this way, most of the powdered material is scraped off the rollers so that the powdered material does not come into engagement with the bare surface of the main cylinder 88.

The transfer scraper 184 is preferably mounted on or connected to the operating lever 236 of the scraper 262 so that the transfer scraper 184 will be swingable with the scraper 202. When the scraper 222 is retracted from the roller 132, the transfer scraper 184 is in its normal operating position, in engagement with or closely adjacent the rollers 139 and 132, as shown in FlG. 3. When the scraper 2il2 is allowed to swing against the roller 132, the transfer scraper 134 is swung in a clockwise direction, away from the rollers 13% and 132 so that the scraper 18 no longer scrapes the powdered material off the rollers 130 and 132. This arrangement revents the powdered developer material from accumulating between the scraper 202 and the lower scraping edge 3.88 of the transfer scraper 184.

The energization of the solenoids 212 and 214 may be controlled manually or by suitable automatic switching equipment which may be provided on the facsimile printing machine. As disclosed and claimed in the previously mentioned Fowlie and Laben patent application Serial No. 206,503, the solenoids 212 and 214 may be controlled by an automatic timer so that the de-energization of the solenoids will be delayed after the movable cutting knife 84- has severed a sheet from the web. The delay in the de-energization of the solenoids insures that the entire document reproduced by the electronic reproducing tube 52 will be developed by the developer 56.

The developer 56 is preferably provided with means for feeding additional toner powder into the receptable or trough 60. Thus, the illustrated developer 55 comprises a feeder 249 (FIG. 10) whereby the powdered toner may be fed from a can or other receptacle 242 into the trough 60. The can 242 may constitute the original container in which the toner powder is supplied by the manufacturer. Thus, it is not necessary to transfer the toner from one container to another before the toner can be used in the developer 56. The can 242 may have a threaded upper portion 244 adapted to be screwed into a threaded flange 246 on a closure or supporting plate 24?. which is mounted on the developer mechanism 53.

To remove the toner powder from the can 242, the feeder mechanism 240 is provided with a feed screw or auger 250 which is mounted within a cylindrical tube 252 adapted to be inserted into the can. The tube 252 extends through and is secured to the supporting closure plate 2 8. It will be seen that the screw 253 and the tube 252 extend 6 into the can 242, closely adjacent the bottom wall 254 thereof. The lower end or" the tube 252 is open and is cut oil along an angle to form a slanting edge 256 so that the lower end of the feed screw 250 will be exposed. Thus, the powdered toner is adapted to be taken up by the screw 250 and carried upwardly through the tube 252 when the screw is rotated. The tube 252 is closely adjacent one side wall portion 258 of the can 242. Moreover, the can 242 is supported at a slanting angle so that the toner powder will gravitate toward the intersection betv een the side wall portion 253 and the bottom wall 254. The lower end of the screw 25% is closely adjacent this intersection so that the screw can remove practically all of the toner from the can 242.

The upper end of the tube 252 is mounted in a bore TH formed in a body or block 252 which is secured to the trough as of the developer 56. A lateral opening 264 (FIG. 4) extends through the tube 252 and the block 1262 and also through a housing or tube 266 so that the toner powder will be fed through the opening 264 by the feed screw 25% into the housing 256. It will be seen from FIG. 4 that one end of the auger r agitating screw 192 is provided with a portion 268 which extends into a bore 27%; formed in the tube or housing 266. The screw portion has double screw flights 272 and 274 adapted to convey the toner powder from the housing 256 into the trough 6%.

It will be understood that the toner powder is carried across the trough 6t) in one direction by the auger 192 and thereby is mixed with the developer composition in the trough. A further mixing action is provided by the other auger 1% which carries the developer composition across the trough in the opposite direction.

In the construction illustrated in FIG. 4, only the screw flight 272 extends along the main portion of the auger 192. Thus, the main portion of the auger has a single screw flight. The feed screw portion 263 of the auger o;

has a central core or shaft 2'76 of relatively small diameter, so that the height of the flights 272 and 274 is relatively great. The main portion of the auger 192 has a core 278 of larger diameter. Between the smaller and larger portions 276 and 278, the core has a flaring or transitional portion 28 At the far end or the auger 192, the core has a tapering portion 282 of gradually decreasing diameter. The screw flight 272 also has a tapering portion 284 of decreasing diameter, so that the feeding capacity of the anger is decreased at the far end. This arrangement facilitates the transfer of the powdered developer composition to the other auger 194 and also avoids the piling up of the developer composition at the far end of the auger.

Adjacent the tapering portions 232 and 284, the other auger 1'94 has double screw flights 236 and 288 which are adapted to take up the powdered material discharged by the auger 122. The double screw flights 23-5 and 22S rapidly feed the powdered developer composition in the opposite direction, part way across the trough 66. Only the screw flight 236 extends all the way across the trough 61 to the near end adjacent the transitional section 280. At the near end, the screw flight 286 has a tapering portion 296 of gradually decreasing diameter to reduce the feedin capacity of the anger at this point, so that the powdered material will not be piled up excessively and will be transferred smoothly to the auger 192.

It is preferred to provide a device 294 for agitating or stirring the toner powder in the can 242, so as to insure that the toner powder will flow downwardly to the lower end of the feed screw 25%. As shown, the stirring device 2% comprises an arm formed from wire and having one end secured to the lower end of the screw 2%, so that the arm will rotate with the screw. in this case, the arm 29 is generally U-shaped and thus has a portion 296 extending upwardly and angling outwardly from the lower end of the screw 250, and a portion 298 which doubles back downwardly from the upper end of the portion 296.

The arm 294 extends a sufficient radial distance from the screw 250 to strike the adjacent side portion 258 of the can 242 during each revolution of the screw. The arm 294 is fiexed inwardly by engagement with the can 242 and then is permitted to spring back outwardly after the arm has passed the adjacent side portion 258 of the can. This inward and outward flexing movement of the arm 294 stirs and agitates the toner powder with an added degree of effectiveness. The arm 294 is preferably made of spring wire so that it may be flexed without taking a permanent set.

To induce further vibration of the arm 294, the tube 252 may be formed with a ridge or projection 3% adapted to be engaged by an inwardly projecting portion 302 of the arm 294 during each revolution of the screw 250. By engagement with the projection 309, the arm 294 is flexed until it snaps past the projection. This snapping action causes the arm 294 to vibrate, so that extremely effective agitation of the toner powder is accomplished.

As shown in FIGS. 10, 12 and 14, a drive 304 is provided for selectively rotating the feed screw 250. As shown, the upper end of the feed screw is connected to a bevel gear 306 which meshes with a second bevel gear 3118. In this case, the bevel gear 308 is secured to a frictional drive wheel 310 which is adapted to be engaged by a second frictional drive wheel 312. Continuous rotation is imparted to the drive wheel 312 by a suitable drive comprising meshing gears 314 and 316. The gear 314 is secured to the drive wheel 312 so as to rotate therewith. The gear 316 is connected to the roller 132 and is rotatable therewith.

To provide for movement of the drive wheel 312 into and out of engagement with the drive wheel 310, the wheel 312 is rotatably mounted on a shaft or pin 320 which is secured to an arm 322 swingable about the axis of the gear 316. When the arm 322 is swung counterclockwise, the drive wheel 312 is moved into engagement with the drive wheel 310. The arm 322 is adapted to be actuated by a lever 326 which is swingable about the axis of the drive wheel 310. It will be seen that the lever 326 has an arm 328 formed with a slot 330 which is slidably engaged with the rear end of the pin 320. Thus, clockwise movement of the lever 326 causes the arm 322 to be swung counterclockwise. A spring 334 may be provided to bias the lever 326 in a counterclockwise direction so that the drive wheel 312 will normally be swung out of engagement with the wheel 310. a

The lever 326 may be actuated manually or by a suitable source of power such as a solenoid 336. As shown in FIG. 12, a link 338 is connected between the solenoid and one arm 340 of a lever 342. The otherarm 344 of the lever 342 is adapted to engage a pin or roller 346 on an arm 348 of the lever 326. A spring 350 may be connected to the arm 340 so as to bias the lever 342 in a clockwise direction, away from the pin 346 on the arm 348. The counterclockwise return movement of the lever 310 is limited by a stop 352 which is adapted to be engaged by the arm 328. An adjustable eccentric stop 354 limits the movement of the arm 328 in a clockwise direction and thus controls the drive pressure between the rollers 310 and 312. The roller 312 is preferably made of rubber or other similar material to provide an effective friction drive.

The solenoid 336 may be energized under the control of the operator to cause additional toner to be fed to the developer trough when needed. Alternatively, a suitable automatic switching arrangement may be provided to energize the solenoid 336 when additional toner is needed.

When the solenoid 336 is energized, the drive wheel 312 is moved against the drive wheel 310, as shown in FIG. 12, so that the wheel 310 and the bevel gear 308 are rotated. The meshing bevel gear 306 rotates the feed screw 250 so that the toner powder is carried upwardly through the tube 252 from the can 242 by the feed screw.

At the upper end of the tube 252, the toner powder is fed through the lateral opening 264 into the housing 266. The continuously rotating screw 268 carries the toner powder from the housing 266 into the trough 60.

In the trough 60, the augers 192 and 194 move the powdered developer composition back and forth across the trough so that the toner is mixed thoroughly with the developer composition. The powdered iron or other magnetic material in the developer composition is attracted by the magnets 116 in the rollers and 132, with the result that the developer composition adheres to the rollers.

When the developer mechanism 56 is in normal operation, the scrapers 200 and 202 are moved away from the applicator rollers 130 so that fairly thick layers of the developer composition are carried upwardly by the rollers against the paper web which is traveling around the mainv cylinder 88. The powdered developer composition brushes against the paper web and is effective to develop any electrostatic image on the web. Some of the toner powder adheres to the electrostatic image, while the powdered iron is retained on the rollers 130 and 132 by the attraction of the magnets 169.

The upper edge 186 of the transfer scraper 184 removes most of the powdered developer from the roller 130 after it has passed the cylinder 88. This material slides down the scraper 184 and is applied to the other roller 132 above the lower edge 188 of the scraper. Thus, the developer is again brushed against the paper web by the second roller 132. The lower edge 188 removes most of the powdered material from the roller 132 as the surface of the roller moves upwardly toward the cylinder 88.

When the developer 56 is to be shut down, the solenoids 212 and 214 are de-energized, whereupon the return springs 208 and 210 cause the scrapers 200 and 202 to swing against the rollers 130 and 132. Simultaneously, the scraper 184 is moved out of engagement with the rollers 130 and 132. The scrapers 200 and 202 scrape most or all of the powdered developer off the rollers 130 and 132 so that the powdered developer will no longer be supplied to the main cylinder 88. When the operation of the developer mechanism is to be resumed, the solenoids 212 and 214 are energized so as to swing the scrapers 200 and 202 away from the applicator rollers 130 and 132. The scraper 184 moves with the scraper 202 to its normal operating position as shown in FIG. 3.

The developer of the present invention has the 'important advantage that the operation of the developer may be started and stopped very easily and quickly, without any need to stop the rotation of the applicator rollers. Thus, it is easy to prevent the accidental application of the powdered developer composition to the bare ,outer surface of the main cylinder. Very little time lag is in volved in the starting and stopping of the operation of the developer. The device for feeding additional toner powder to the developer may also be controlled very easily and precisely. .Any waste or spillage of the powdered developer composition may readily be avoided. Thedeveloper composition is kept well mixed at all times so that the developing action is sufiicient and uniform.

Various modifications, alternative constructions and equivalentsmay be employed without departing from the true spirit and scope of the invention, as exemplified in the foregoing description and defined in the following claims.

We claim: 1. In a developer utilizing a powdered developer composition having a component made of magnetic material, the combination comprising first and second applicator rollers having magnetic means therein for attracting the powdered developer composition, means for rotating said first and second rollers in the same direction, a transfer scraper disposed in an inclined position between said rollers and having a first edge adjacent said first roller and a second edge adjacent said second roller for transferring the developer composition between said first and second rollers,

a receptacle under said rollers for receiving the de veloper composition,

first and second control scrapers movable toward and away from said first and second rollers for removing the developer composition from said rollers to stop and start the operation of the developer,

said transfer scraper being connected to said second control scraper and being movable away from said first and second rollers when said second control scraper is moved toward said second roller,

and means for selectively moving said first and second control scrapers toward and away from said first and second rollers for controlling the operation of the developer.

2. In an applicator for utilizing a powdered material including a component having magnetic properties,

the combination comprising a receptacle for holding a supply of the powdered material, at least one applicator roller rotatably mounted in said receptacle and having magnetic means thereon for attracting the powdered material,

a container for holding a supply of powder to replenish the supply in said receptacle,

a conduit leading from said container and communicating with said receptacle,

a feed screw rotatable in said conduit for feeding the powder along said conduit from said container to said receptacle,

a selectively operable drive for selectively rotating said feed screw,

a flexible agitating arm secured to said feed screw and rotatable therewith in said container,

said agitating arm extending away from said feed screw and being engageable with the wall of said container for removing powder therefrom,

and an outwardly projecting element on said conduit and extending into the path of said agitating arm for engagment by said agitating arm during each revolution thereof,

said agitating arm being adapted to flex and snap past said projecting element.

3. In an applicator for utilizing powdered material having magnetic properties,

the combination comprising a receptacle for holding a supply of the powdered material,

first and second applicator rollers rotatable in said receptacle and having magnet means for attracting layers of the powdered material to said rollers,

means for rotating said rollers in the same direction, a transfer scraper disposed in an inclined position between said first and second rollers and having an upper edge adjacent said first roller for scraping powdered material therefrom and a second edge adjacent said second roller for scraping powdered material therefrom, said transfer scraper having a portion for carrying powdered material between said first and second edges to transfer the powdered material scraped from said first roller to said second roller, the material scraped from said second roller by said second edge being returned to said receptacle,

and first and second control scrapers movable toward and away from said first and second rollers for selectively removing the powdered material from said rollers to control the operation of said applicator.

4. In an applicator for utilizing powdered material including a component having magnetic properties,

the combination comprising a receptacle for holding a supply of the powdered material,

first and second applicator rollers rotatable in said receptacle,

magnet means on each of said rollers for causing a layer of the powdered material to adhere to each roller, means for rotating said rollers in the same direction,

a transfer scraper disposed between the rollers and having one edge for removing material from said second roller and another edge for transferring material from said first roller to said second roller,

and first and second control scrapers selectively movable toward and away from said first and second rollers for selectively removing the material from said rollers to control the operation of said applicator,

said transfer scraper being connected to one of said control scrapers and being movable therewith away from said rollers when the corresponding control scraper is moved toward the corresponding roller.

5. In an applicator for utilizing a powdered material including a component having magnetic properties,

the combination comprising a receptacle for holding a supply of the powdered material,

a separate container for holding a supply of powder to replenish the supply in said receptacle,

at least one applicator roller rotatably mounted in said receptacle and having magnetic means thereon for attracting the powdered material,

a conduit extending between said container and said receptacle,

a feed screw rotatable in said conduit for feeding the powder along said conduit from said container to said receptacle,

a drive for rotating said feed screw,

and a flexible agitating arm having one end secured to said feed screw,

said agitating arm having a free end extending outwardly from said feed screw into said container, said arm being rotatable with said feed screw,

said container having wall portions in the path of said agitating arm and engageable by said arm,

said arm being flexed by engagement with said Wall portions and thereby being enabled to pass said wall portions to scrape the powder therefrom.

6, In an applicator for utilizing a powdered material including a component having magnetic properties,

the combination comprising a receptacle for holding a supply of the powdered material,

at least one applicator roller rotatably mounted in said receptacle and having magnetic means thereon for attracting the powdered material,

a separate container for holding a supply of powder to replenish the supply in said receptacle,

a conduit extending between said container and said receptacle,

a feed screw rotatable in said conduit for feeding the powder along said conduit from said container in said receptacle,

a drive for rotating said feed screw,

a flexible agitating arm havinr one end secured to said feed screw and rotatable therewith,

the other end of said agitating arm extending freely into said container for rotation therein,

and an outwardly projecting element on said conduit and extending into the path of said agitating arm for engagement by said agitating arm during each revolution thereof,

said agitating arm being adapted to flex and snap past said projecting element to knock the powder loose around the agitating arm.

7. In an applicator for utilizing powdered material including a component having magnetic properties,

the combination comprising a receptacle for holding a supply of the powdered material,

first and second parallel applicator rollers rotatable in said receptacle,

magnet means on each of said rollers for causing a layer of the powdered material to adhere to each roller,

means for rotating said first and second rollers in the same direction,

and a transfer scraper disposed between said first and second rollers and having a first edge adjacent said References Cited in the file of this patent UNITED STATES PATENTS Reuter Apr. 11, 1961 Streich Oct. 10, 1961 Magnusson May 1, 1962 Frantz et al Mar. 19, 1963 Sugarman May 7, 1963 Keller et a1. July 23, 1963 

1. IN A DEVELOPER UTILIZING A POWDERED DEVELOPER COMPOSITION HAVING A COMPONENT MADE OF MAGNETIC MATERIAL, THE COMBINATION COMPRISING FIRST AND SECOND APPLICATOR ROLLERS HAVING MAGNETIC MEANS THEREIN FOR ATTRACTING THE POWDERED DEVELOPER COMPOSITION, MEANS FOR ROTATING SAID FIRST AND SECOND ROLLERS IN THE SAME DIRECTION, A TRANSFER SCRAPER DISPOSED IN AN INCLINED POSITION BETWEEN SAID ROLLERS AND HAVING A FIRST EDGE ADJACENT SAID FIRST ROLLER AND A SECOND EDGE ADJACENT SAID SECOND ROLLER FOR TRANSFERRING THE DEVELOPER COMPOSITION BETWEEN SAID FIRST AND SECOND ROLLERS, A RECEPTACLE UNDER SAID ROLLER FOR RECEIVING THE DEVELOPER COMPOSITION, FIRST AND SECOND CONTROL SCRAPERS MOVABLE TOWARD AND AWAY FROM SAID FIRST AND SECOND ROLLERS FOR REMOVING THE DEVELOPER COMPOSITION FROM SAID ROLLERS TO STOP AND START THE OPERATION OF THE DEVELOPER, SAID TRANSFER SCRAPER BEING CONNECTED TO SAID SECOND CONTROL SCRAPER AND BEING MOVABLE AWAY FROM SAID FIRST AND SECOND ROLLERS WHEN SAID SECOND CONTROL SCRAPER IS MOVED TOWARD SAID SECOND ROLLER, AND MEANS FOR SELECTIVELY MOVING SAID FIRST AND SECOND CONTROL SCRAPER TOWARD AND AWAY FROM SAID FIRST AND SECOND ROLLERS FOR CONTROLLING THE OPERATION OF THE DEVELOPER. 